Pile and pile driving apparatus



PILE AND PILE DRIVING APPARATUS Filed Dec. 24, 1956 5 Sheets-Sheet 2 Y r 1 BYfl Q J 41 6 w mbL VQM April 18, 1961 H. F. CAUDILL PILE AND PILE DRIVING APPARATUS 5 Sheets-Sheet 5 Filed D80. 24, 1956 United States Patent 2,979,912 PILE AND PILE DRIVING APPARATUS Howard F. CaudilhArlington Heights, Ill. (Rte. 2, Box 222, Lutz, Fla.)

The present invention relates to an improved pile and pile driving apparatus. The invention has particular reference to tubular steel pileswhich are adapted to be driven down into the ground by a driving core or mandrel. After the tubular pile shell has been driven to the depth desired, the driving core is removed, following which the pile shell is usually filled with concrete, which in some instances is reinforced with reinforcing rods extending down into the pile shell.

More particularly, my invention has primary application to tubular steel piles which have the required wall thickness and sectional area of steel to qualify under building codes as steel pipe piles, but which do not have sufficient rigidity and strength to withstand being driven into the ground without being supported or reinforced by a removable driving core or mandrel.

These pile shells are usually driven into the ground with a driving point on the lower end thereof, and one of the objects of the invention is to create an improved locking joint between the pile shell and its driving point which will compel the pile shell to follow down with the driving point as the point is being driven down into the ground by the driving core. This object is attained by providing an improved expansible type of driving point on the pile shell, and by providing an improved expanding device on the driving core, which coact with each other under downward driving force transmitted through the core, so as to expand the driving point outwardly into the side wall of the pile shell, thereby creating outwardly projecting interlocking bulges in the driving point and in the wall of the pile shell. These interlocking bulges establish a locking joint which can carry the driving blows of the pile driving hammer without injury, as has been proven by the successful driving of a large number of piles. The attempted practice of welding the driving point to the pile shell has been unsuc- L cessful because the driving blows tear the welded joint loose.

Another object of the invention is to provide an improved sectionalized driving core or mandrel made up of end-to-end sections joined together by improved coupling devices which-during the core driving operationestablish substantial axial rigidity between the adjacent core sections, but which-during the core withdrawing operation-permit loose articulation and free angular deflection between the adjacent core sections. The axial stiffness or relative rigidity between core sections during the driving operation facilitates the driving operation by minimizing any tendency of the core assembly to bow laterally or to assume a lateral sweep curvature On the other hand, the loose angula'rly deflectible connection between adjacent core sections, which is prevalent during the core withdrawing operation, facilitates the withdrawal of the core; particularly if the pile has been subjected to a lateral sweep by striking aheavy boulder or rock formation in the pile driving operation, requiring that the core be withdrawn through the curvature of this sweep. I A i Another object of the invention is to provide an improved, multiple-diameter pile shell and an improved multiple-diameter driving core for driving such a shell. This multiple-diameter shell comprises an upper shell section of relatively large diameter and a lower shell section of relatively small diameter, or a series of shell sections of successively smaller diameters, all secured together.

Another object of the invention is to provide improved coupling connections between adjacent core sections which establish locking joints between the coupling connections and the pile shell. In one embodiment of [the invention, these locking joints are created by expansible rings which are carried by each coupling connection, and which are adapted to be wardly thereby in the driving operation, whereby to create outwardly expanded locking bulges in the pile shell which lock the shell to the core assembly. In another embodiment of the invention, these expanding coupling connections occurat the joints between upper and lower core sections of different diameters adapted for driving upper and lower pile shells of different diameters. In both embodiments of'the invention, these locking joints or bulges occur at the vertically spaced locations of the coupling connections between adjacent core sections, so that the stress of compelling the pile shell to follow the driving core down into the ground is applied to the shell at distributed points along its length.

Other objects, features and advantages of the invention will be'apparentfrorn the following detailed description of certain preferred embodiments thereof. In the accompanying drawings illustrating such embodiments:

Figure 1 is 'a fragmentary vertical sectional view through the lower portion of the driving core and lower end of the pile shell with its driving point, showing th e'driving core in elevated position prior to being forced down into its expanding position within'the driving point.

Figure 2 is a similar view showing the driving core forced down into driving position within the driving point,'in which position it has expanded the driving point and pile shell outwardly to establish thelocking joint therebetween. i p

V Figure 3 is a fragmentary axial section through one of the coupling connections which serve to couple adjacent core sections, this coupling connection being shown in its-flexible loose state, with its expansion ring in its normal un-expanded condition.

Figure 4 is a view similar to Figure 3 showing the coupling connection driven together in core driving relation, with the expansion ring expanded outwardly to establish the locking bulgev in the pile shell.

Figure 5 is a transverse sectional view taken approximately on the plane ofv the line 55'of Figure 3, illustrating the expansion ring in its contracted condition;

Figure 6 is a fragmentary vertical sectional View of the upper end of the pile shell and pile driving core on a smaller scale, illustrating the pile driving hammer and anvil.

Figure 7 is a vertical sectional view through an improved multiple-diameter pile shell and through my improved multiple-diameter driving core for driving such pile shell;

Figure 8 is a similar view showing the expanded looking joint established in the multiple-diameter pile shell by the expansible action of the coupling in the multipleliameter driving core, and

Figure 9 is a similar view showing the connection of the latter core with the point driving plug.

The driven portion of my improved pile comprises a tubular pile shell 10 and a pentrating point or cap 12 which closes the lower end of the tubular shell 10. The

Patented Apr. 18, 196i expanded out-- shell in is preferably composed of steel tubing or straight cylindrical pipe stockhaving both ends open and being of uniform diameter from end to end and having either a longitudinal or spiral seam. The wall thickness of the shell 1%) will vary, depending upon different driving conditions, load bearing conditions, etc., but under average conditions will generally range somewhere between #18 gauge to about #8 gauge or thicker, and for average installations the shell 10 will have a diameter ranging upwards from 10 to 12 inches. As previously described, the pile shell It) has sufiicient thickness of wall to qualify under the building codes as a straight cylindrical steel pipe pile, but, for reasons of economy, does not have sufficient thickness of wall to enable it to be driven into the ground by driving blows imparted to the upper end of the pile and acting in compression down through the length of the pile. Instead the wall thickness is preferably such that the pile must be driven by a core and a driving point so that the pile is pulled into the ground in tension by being compelled to follow the driving point down into the ground.

The driving point 12 is constructed of a malleable steel casting, or of fabricated steel, of substantially thicker metal than the pile shell 19, and comprises a downwardly curved lower penetrating portion 14 and an upwardly extending cylindrical skirt portion 16. The penetrating or base portion 14 may be formed with diametrically extending internal cross ribs 18 which strengthen this base portion and which also define an upwardly facing driven surface 20 which receives the driving impact of the driving core 35 which is inserted down into the pile shell, this driving core having a lower downwardly facing driving surface 46 which is adapted to have driving abutment against the driven surface 20 of the driving point 12 during the operation of driving the pile shell Iii into the ground, as will be later described in conjunction with Figure 2. The convexly curved base portion 14 extends outwardly beyond the skirt portion 16 to define a projecting annular lip 22 forming an upwardly facing shoulder 24. The pile shell 10 fits down over the skirt portion 16, with its lower edge abutting the shoulder 24. Surrounding the lower end of the pile shell, and secured thereto by welding or riveting, is a steel reinforcing band 26, which preferably has its lower edge also abutting against the shoulder 24.

Formed in the upper edge of the skirt portion 16 is a plurality of downwardly extending slots 30 which define therebetween a plurality of upwardly extending expansion fingers 32. The slots 30 are so proportioned in length that when the pile shell 10 and driving point 12 are in the assembled relation shown in Figure 1 the lower ends of the slots 30 terminate substantially at the top edge of the reinforcing band 26. Projecting inwardly from the upper end of each arcuate expansion finger 32 is a pressure or contact bead 34 having a rounded inner surface.

Referring now to the driving core, which is designated 35 in its entirety, this is inserted down into the pile shell 10, preferably after the pile shell 10 has been lowered down over the driving point 12 in the assembly operation which is performed between the hammer leads of the pile driver. The outside diameter of the driving 4 is a driving plug or head 36 which is preferably con-- structed in the form of a steel forging or steel casting. This plug or head has a downwardly and inwardly tapering conical surface 38, the lower end of which has entering clearance into the beaded upper ends of the expansion fingers 32. As the driving core is forced down into the driving point 12 this conical surface 38 wedges or spreads. the beaded upper edges 34 of the fingers 32 outwardly.v When the lower driving surface 40 of the driving head 36 has been forced down into abutment against the upper driven surface of the driving point 12, the fingers 32 have all been expanded or pressed outwardly against the inside of the shell 10, thereby forming an annular locking bulge 42 in the wall of the pile shell, the lower por-- tion of which bulge 42 continues downwardly and inwardly on a long tension transmitting taper or constriction 42a. 1 The lower end of this tension transmitting taper or constriction 42aterminates substantiallyabove the lower core 35 closely approximates the inside diameter of the pile shell 10 from the top of the pile shell down to a driving plug or head 36, but the driving core is of slightly smaller diameter so that a circumferential freeslipping clearance space 37 is established between these outside and inside diameters. This circumferential freeslipping clearance space 37 is constantly maintained between the driving core and pile section throughout the entire operation of driving the pile section into the ground, and of thereafter withdrawing the driving core end of the pile shell, i.e. substantially where the shell wall resumes its original diameter at the point where theexpansible fingers 32 merge with the skirt 16. This operation of forming the expanded annular bulge'42 and tension transmitting taper 42a by outward spreading of the expansion fingers 32 is preferably performed at or near ground level between the leads of the pile driver. In the assembly operation, the pile shell 10, driving point 12 and driving core 35 can be assembled together in different sequences of steps; i.e. in one sequence the driving point can first be assembled in the lower end of the pile shell and the driving core thereafter inserted down into the upper end of the pile shell; or as an alternative sequence, the drivingcore can first be inserted into the pile shell and the pile shell then lowered down over the driving point. Iprefer to follow the latter sequence wherein the pile shell is first supported in the pile driver leads, and the driving core is then inserted down into the pile shell. Thereafter, the pile shell is lowered down over the driving point, with the latter resting upon some solid reaction base, following which the driving core and pile driving hammer are dropped down to swage the expansible fingers 32 outwardly. It may be necessary to impart one or two power driven blows of the pile driving hammer to effectively swage the fingers 32 outwardly and to deform the surrounding side wall of the shell 10 outwardly to form the locking bulge 42. Thereupon, the shell 10, driving point 12 and driving core 35, in the assembled relation shown in Figure 2, are started down into the ground in the pile driving operation. The expanded locking bulge 42 and tension transmitting taper 42a formed in the shell securely lockthe lower end of the shell to the driving point 12 and compel the shell to go down into the ground along with the driving point 12, under the impact of the blows transmitted downwardly to this point through the driving core 35. This follows from the fact that the tension transmitting taper 42a in the wall of the pile shell matches perfectly with the tension transmitting taper or constriction 32a of the expansible fingers 32, which latter taper has formed the taper 42a in the wall of the pile shell. The wedging frictional engagement between these two tension transmitting tapers or constrictions .2a and 32a transmits the driving blows of the pile driving hammer from the core 35 through the driving point 12 to the pile shell lit for pulling or drawing the pile shell 10 down into the ground solely or primarily under tension stress acting downwardly on the lower portion of the pile shell 10. It will be seen that in this relationship the inner tapering surface 32a formed externally 0n the fingers 32 of the from the pile section. The driving core 35 is adapted to receive the blows of the pile drivinghammer 112 (Fig. 6) on its upper end. At the lower end of this driving core driving point12 constitutes the driving taper. and that the outer tapering surface 42a formed internally within the pile shell 10 constitutes the driven taper. The reinforcing band 26 on the lower end of the shell prevents the lower end of the shell from expanding further outwardly and working upwardly along the outer surfaces of the expansion fingers 32, and thereby prevents separation of the shell from they point. In other Words, when extremely hard driving conditions, are encountered, this steel reinforcing band 26 functions to maintain the lower end of the pile shell 10, substantially at its original diameter, so that all of the bulging deformation 42 occurs in the side wall of the pile shell at a point'spaced upwardly from the lower end of the shell. There is enough give or shock absorbing yieldability in the wedging frictional grip between the two tension transmitting tapers 32a and 42a to prevent the driving point 12 from tearing loose from the pile shell through disruption of the shell wall, as has been established by the successful driving of a large number of pile shells in the practice of my invention. Previous attempts to drive, with an inside mandrel or core, pile shells which were welded to the driving points have not been successful because the driving blows tear the point or head loose from the shell. The outwardly projecting annular lip 22 on the driving point functions as a plow in the driving operation to establish earth clearance to reduce friction of the soil on the pile shell during driving.

After the pile shell 10 has been driven into the ground to the desired depth, an upward hoisting-pull is exerted on the driving core 35 for causing the conical surface 38 of the driving head 36 to break loose from its wedging fit within the expansion fingers 32and skirt portion 16 of the driving point 12. Thereupon', the drivingcore 35 is lifted entirely out of the pile shell, leaving the driving point 12 anchored in the lower end of the shell and serving to close off the bottom of the shell. The shell is now in readiness for receiving its fill of concrete, which, in some instances, may be reinforced by reinforcing rods, I-beams or the like inserted down into the shell, usually prior to the dumping of the concrete.

During the driving operation, and after the completion of the driving operation while the pile shell is awaiting the placing of its concrete fill, the closed bottom 14 and closed skirt portion 16 of the driving point 12 prevent the entrance of water or dirt into the lower endof the pile shell 10. This water-tight, dirt-tight joint is established between the skirt portion 16 and theinner surface of the pile shell 10, particularly after the upper edge of the skirt portion 16 has been expanded outwardly into a tight compressive fit within the shell 10 under the expanding action of the conical surface 38.

Referring now to the previously described feature of axial rigidity during driving and loose articulation during removal, which characterizes the driving core 35, this comprises one or more tubular sections 45a, 45b, etc. of relatively heavy cylindrical stock. The lower section 45a is joined to the driving plug or head 36 by a cone pling sleeve 48 and coupling pin 50. The main portion of the coupling sleeve 48 extends up into the lower end of the tubular section 45a, but the lower portion of the coupling sleeve is formed with an outwardly projecting shoulder 52, against which are transmitted the driving blows of the power driving hammer effective on the upper end of the driving core. The lower end of the coupling sleeve transmits these blows to an annular driving shoulder 54 formed around the driving plug 36.

Extending upwardly from the driving plug 36 is an upwardly tapered conical coupling shank 56, which passes upwardly through a conically tapered bore 58 in the coupling sleeve 48. The pin 50 is passed through al gned holes 60, 62 and 64 formed respectively in the tubular section 45a, coupling sleeve 48 and conical shank or tongue 56, this pin being readily removable for uncoupling the driving plug 36 from the lower end of the core, section 45a.

The transverse opening 64 in the conical shank 56 is Pr r y ongated v r i a y. a ustra ed; in order to create a loose laterally tiltable joint between the core section 45a and the driving plug 36.wh en upward pull is exerted on the'core section in the core withdrawing operation.

The vertical lost motion or' play which is eration of releasing the core.

per itted by the s ctdike penin 4: also Pr i or impact jarring to loosen the driving plug 36 from the driving point 12 in the operation of withdrawing the core from the driven pile. The matching conical taper between the coupling shank 56 and bore 58 establishes stiffness between the driving plug 36 and core section 45a in the operation of driving the pile; while affording flexibility or looseness between these parts as soon as upward pull is exerted on the core section 45a and the matching conical surfaces separate in the operation of removing the core. The upper end of the slot-like opening 64 and the upper surface of the coupling pin 50 constitute cooperating stop means for limiting this relative separating movement between the tapered plug 56 and tapered bore 58.

When the driving core is made up of two or more core sections 45a, 45b, etc., these successive core sections are joined together by coupling connections 65, illustrated in Figures 3 and 4. Each of these coupling connections comprises a coupling head 66 which is provided with a shank portion 68 fitting down into the upper end of the tubular core section 45a, 4511, etc., and which is also provided with an outwardly projecting shoulder 70 for abutment against the upper edge of the core section 45a, etc. This coupling head 66 is welded or riveted to the upper end of the tubular core section; Extending upwardly from the coupling head 66 is a conical coupling plug or tongue 72, similar to the conical coupling tongue 56 shown in Figures 1 and 2. This conical coupling tongue 72 fits into the conical bore 74 of a coupling sleeve 76 which is mounted in the lower end of the next succeeding core section 45b, etc. The coupling sleeve 76 has a shoulder 78 against which the lower end of the tubular core section transmits downward driving blows. The lower end of the coupling sleeve 76 has a driving surface 80 adapted to transmit driving blows downwardly against an upper driving surface 82 on the coupling head 66 of the next lower core section.

A transverse coupling pin 84 passes through aligned holes 86, 88 and 90 formed in the core section 4512, coupling sleeve 76 and coupling tongue 72 respectively. The hole 90 in the coupling tongue 72 is elongated vertically to afford vertical lost motion between the tapered tongue 72 and the tapered bore 74. As shown in Figure 4, these two matching tapered surfaces are substantially in driving engagement when the driving surface 80 on the lower end of the coupling sleeve 76 is in driving engagement against the driving surface 82 on the coupling head 66. These matching tapered surfaces afiord stilfness in the core assembly during the driving operation; and, conversely, they permit quickacting flexibility or looseness between the core sections in the operation of removing the core. This flexibility and angular play which is thus permitted between the core sections in the core removing operation overcomes all tendency of the core to bind under those conditions where the pile has been subjected to sweep in the driving operation. This sweep or lateral deflection of the pile frequently occurs in a pile driving operation as a result of the driving point striking a large boulder or other obstruction and being deflected laterally. Heretofore, when using a solid core, it was frequently impossible to remove the core when the pile had been subjected to a substantial degree of lateral sweep. This difliculty has all been avoided by the above described tapering fits between the coupling parts 66 and 76, and by the elongated holes 90 cooperating with the pins 84, the upper end of each elongated hole 90 and the upper surface of coupling pin 84 constituting cooperating stop means for limiting the separation of these tapering fits. The provision of the elongated holes 90 also permits impact jarring to be transmited in an upward direction from one core section to the other in the op- The pins 84 are remov- 7 able above ground level to permit uncoupling of the coupling parts 66 and 76.

In Figures 3 and 4 I have also shown each coupling connection 65 as being provided with an expansion ring 92 which responds to downward lost motion between the coupling sections 66, 76 to create outwardly acting expansion forces in thepile shell to bulge the shell outwardly at each coupling connection 65. This expansion ring 92 seats on the driving surface 82 of the lower coupling section 66. The upper coupling section 76 is formed at its lower end with an annular tapered surface 94 which is adapted to be formed down into the inside of the expansion ring 92 when the upper coupling section 76 is forced downward through its range of lost motion relative to the lower coupling section 66, such ring expanding operation occurring either when the coupling connection 65 is between the leads of the pile driver, or when the coupling connection 65 is in the ground in the pile driving operation. The expansion ring 92 is preferably of split spring steel construction, as shown in Figure 5, adapted to be expanded outwardly to a larger outside diameter by the action of the tapering surface 94. The outward force set up in this expansion ring 92 creates an outward bulge 96 in the pile shell 10. This annular bulge 96 functions as a mechanical locking formation to prevent relative sliding movement between the pile shell and the core in the driving operation, i.e. this bulge compels the shell to go downwardly with the driving core 35. In addition, the annular bulge 96 serves as a plow ring for expanding the earth walls as the pile is being driven downwardly through the ground. If desired, the shell 10 may have a reinforcing band 98 welded or riveted thereto at each point or zone where the rings 92 create outward expansion. This band 93 may serve as a coupling band for coupling or joining the adjacent ends of upper and lower pile sections together. In the core withdrawing operation the expansion tapers 94 move up out of the rings 92 and these rings contract back substantially to their original diameters, thereby restoring the loose angularly tiltable freedom to the coupling connections 65, and permitting easy withdrawal of the core assembly.

The expansion rings 92 are an optional feature which may or may not be employed with the sectionalized core. Alternatively, the expansion rings may be left out of some of the coupling connections 65 and included in other of the coupling connections, these coupling connections operating equally well whether or not the expansion rings 92 are included therein.

Successive sections of the pile shell 10 may be joined together by conventional welding or in any other preferred manner.

In Figure 6 I have shown a driving anvil 102 detachably secured to the upper end of the uppermost core section, which I have designated 452. This anvil has a tapering socket 104 into which fits a tapering tongue or pin 106 projecting upwardly from an upper coupling head 108 secured in the core section 45s. A transverse pin 116 passes through the depending skirt portion of the anvil and through the tapering pin 106, for detachably securing the parts together. The hammer element of the pile driver, which is adapted to strike the pile driving blows against the driving anvil 102 is diagrammatically indicated at 112.

In some situations, it is the practice to use multiplediameter or step taper piles wherein each completed pile comprises a connected sequence of different size pile shells, with the large diameter shell at the top and the small diameter shell at the bottom. In Figures 7 and 8 I have shown an improved construction of multiplediameter pile shell, and an improved construction of a multiple-diameter driving core for driving such pile. The improved multiple-diameter pile is shown as comprising an upper pile section lila of relatively largediarneter,

and a lower pile section 10b of relatively small diameter, these two diameters being typically represented by 12 inches for the upper section and 11 inches for the lower section. It will be understood that the completed pile might comprise three or more sections, with larger stepped sections occurring above the upper section 1011, or with smaller stepped sections occurring below the lower section 10b.

The adjacent ends of the upper and lower pile shell sections 10a and 10b are joined together in an improved overlapping joint 115. This joint overlaps a substantial distance, and interposed between these overlapping ends of the pile shells is an intervening joint band 116, preferably composed of steel. This intervening band 116 is externally welded at its lower end to the upper and lower pile sections, as indicated at 117. Formed in the upper edge of the band 116, and also extending through the upper edge of the lower pile shell 10]; are a plurality of uniformly spaced downwardly extending slots 119, which define therebetween a plurality of upwardly extending expansion fingers 120, comparable to the expansion fingers 32 of the driving point 12. These expansion fingers 120 permit the formation of an outwardly extending locking bulge between the stepped joint 115 and the multiplediameter driving core 35a, which will now be described.

This multiple-diameter driving core 35a comprises an upper core section 450 of relatively large diameter to have a snug sliding fit within the large diameter upper pile section 16a, and also comprises a lower core section 45d of relatively smaller diameter to have a snug sliding fit within the small diameter lower pile section 16b. These two core sections 450 and 45d are joined together by a coupling connection 121 which serves to expand the fingers 126 into the locking bulge and to establish a rigid driving connection between the core sections in the pile driving operation; but which coupling connection relaxes into a loose laterally deflectable connection in the core withdrawing operation. This coupling connection 121 comprises a coupling head 122 which is provided with a shank portion 123 fitting down into the upper end of the lower core section 45d. The coupling head also comprises a lower cylindrical portion 12 having the smaller diameter of the lower core section, and an upper clyindrical portion having the larger diameter of the upper core section. Flaring outwardly and upwardly between these two cylindrical portions is a long conical portion 126, which is operative to exert an expansion action on the expansion fingers 120, as will be later described. The lower cylindrical portion 124 is welded to the upper end of the lower core section 45d, as indicated at 127. Formed at the top of 'the upper cylindrical portion 125 is a radially extending annular driving surface or shoulder 129 for receiving driving blows from the upper core section. Rising axially from the center of this annular driving surface 129 is a conical shank 72a which passes upwardly through a conically tapered bore 740 in a coupling sleeve 76a. This coupling sleeve 76a comprises two longitudinally split halves which are assembled over the tapered shank 72a, and are then welded in place in the lower end of the upper core section 45c, as indicated at 131. The lower radial surface 132 of the coupling sleeve 76a constitutes an upper core driving surface which is adapted to transmit driving blows to the lower core driving surface 129 in the pile driving operation. The upper .end of the tapered shank 72a is formed with a cylindrical head 134 which is joined to the shank with a beveled filet or flare 135. The upper end of the conical bore 74a has a correspondingly flared surface 136 to receive the flare 135. The length of the tapering shank 72a exceeds the length of the tapering bore 74a to permit vertical lost motion or play therebetween, for the purpose of producing a loose, laterally inclinable joint during the core withdrawing operation. During the pile driving operation, shownin Figure 8, the tapering shank 72a engages .with relatively tight wedging fit within'the tapering bore 74a, while the radial driving surfaces 129. and 132 are in abutment, thereby producing a relatively rigid joint between the two core sections for transmitting the pile driving blows.

Referring now to the expansion action of the tapered expansion surface 126 on the expansion fingers 120, in the assembly of the driving core Within the multiplediarneter shell, the core moves downwardly within the shell until the long tapered expansion surface-126 engages the upper edge of the overlapping joint 115. Thereupon, driving blows are transmitted from the pile driving hammer to the upper end of the driving core, forcing conical taper 126 down into the band 116, thereby spreading the expansible fingers 120 which are formed in the upper edge of the intervening band 116 and in the upper edge of the lower pile shell b in an outward direction, such outward expansion of the fingers 120 also expanding or deforming the side wall-portion of the outer upper pile shell 10a, so as to create the outwardly projecting locking bulge 138 and tension transmitting taper 138a (Figure 8). This locking bulge 138 and tension transmitting taper 138a serve to lock the upper pile shell 10a directly to the tension transmitting taper 120a of the expansible fingers 120 which in turn is driven by the wedging taper 126 on the driving core at the step joint 115, so that the tension required to draw the upper shell 10a down into the ground is transmitted directly from the driving core to the base endof this upper shell 10a through the locking bulge 138 and tension transmitting taper 133a, and hence this tension need not be transmitted upwardly through the lower shell 1%. Thus, the driving tension for driving the pile shell downwardly against earth friction is applied at distributed points along the length of the pile shell. lnaddition, the annular bulge 138 serves as a plow ring for expanding the earth walls as the pile is being driven downwardly into the ground. 7

The creation of the locking bulge 138 may be effected while the pile shell is disposed above ground between the leads of the pile driving hammer, or itrnay take place in the initial phase of driving the pile'shell into the ground. In the core withdrawing operation, the couplingsleeve 75LIIXOV6S upwardly along the coupling shank 72a until the upper end of this coupling sleeve 76a engages the underside of the shank head 134, the upper end of the coupling sleeve 76a and the underside of the shank head 7 134 constituting cooperating stop means for limiting the relative upward separatingmotion between the coupling sleeve and coupling shank. This introduces clearance space between the tapering surfaces of the coupling sleeve 76a and of the coupling shank 72a so that the axis of the lower core section can incline laterally relatively to the axis of the upper core section, thereby enabling the flexible loose jointed core to follow around any sweep curvatrue which may have been set up in the pile shell during the driving operation. The vertical lost motion between the tapered shank 72a. and the tapered bore 741; of couplingsleeve 76a alsopermits impact jarring to be transmitted in an'upward direction from'one coresection to the other in the operation of releasing the core.

It will be understood that the core coupling connection 7.2 rr, 76r1 of Figures 7 and 8 can be used in the embodiments shown in Figures 3 and 4 in place of the core coupling connection 72, 76; and, conversely it will be understood that the core coupling connection 72,. 76 of Figures 3 and 4 can be used in the embodiment shown in Figures 7 and 8 instead of the core coupling connection 72a, 76a. i i i I In Figure 9, l have shown the coupling connection 72a, 76d er Figures 7 and 8 associated with the driving point expansion plug 36 of Figures 1 and 2Q This coupling shank "72 and coupling sleeve 76:: function analogously to the conical coupling plug 56 and to the coupling sleeve 48 of Figures 1 and 2. i i i While I have illustrated and described what I regard to be the preferred embodiments of the invention, neverin theless it will be understood that such are merely egrgnrr-w plary and that numerous modifications and rearrange:

ments may be made therein without departing from the essence of the invention.

I claim:

1. In pile apparatus of the class described, the combina? tion of a relatively thin wall cylindrical pile shell of substantially uniform diameter for the major portion of its length, a substantially cylindrical driving core freely re-, ciprocable throughout the length of said cylindrical pile shell, said driving core having an outside diameter almost equal to the inside diameter of said pile shell, a driving head carried at the lower end of said driving core having a downwardly and inwardly tapered wedging surface and formed with adownwardly facing driving surface below said wedging surface, a driving point at the lower end of said pile shell including an end head formed with an upwardly facing driven surface adapted to receive driving blows from the downwardly facing driving surface of said core in the pile driving operation, said end head also establishing a lower end closure closing off the bottom end of said pile shell, said driving point being of thicker metal than said pile shell and comprising a circularly arranged series of upwardly projecting expansible fingers each having an inwardly extending pressure bead at its upper end, said expansible fingers extending upwardly within the lower end of the pile shell, said lower end of the pile shell .and said expansible fingers being expandedoutwardly into a corresponding conical formation by the swaging action of'the tapered wedging surface on said driving head being forced downwardly against thering of pressure beads in a swaging operation so as to rigidly join said driving point to the lower end of said pile shell before starting to drive the shell into the ground, said tapered wedging surface having an upper maximum diameter which is substantially larger than the internal diameter ofsaid ring of pressure beads, said upper maximum diameter having a vertical spacing above. said downwardly facing driving surface on said core which is substantially equal to or slightly less than the vertical spacing of said ring of pressure beads above said upwardly facing driven surface within said point, whereby said tapered wedging surface will complete the outward swaging of said expansion fingers before said driving surface engages said driven surface to start the downward driving of the pile shell, the conical formation assumed by said expansible. fingers constituting a tension transmitting driving taper and the conical formation assumed by said shell constituting a tension transmitting driven taper, through the engagement of which tapers the downward driving blows on the driving core are transmitted from the driving head to the pile shell for drawing the pile shell down into the ground under downwardly acting tension applied to the lower end of the pile shell.

2. In pile apparatus of the class described, the combination of a relatively thin wall pile shell of substantially uniform cylindrical diameter for the major portion of its length, a substantially cylindrical driving core freely reciprocable'within said pile shell, said driving core having an outside diameter almost equal to the inside diameter of said pile shell, a downwardly and inwardly tapered-wedging surface on the lowerportion of said driving core and a downwardly facing driving surface at the lower end of said core, a driving point at the lower end of said pile shell of thicker metal than said pile shell and formed with an upwardly facing driven surface adapted to receive driving blows from the downwardly facing driving surface of said core in the pile driving operation, said driving point also comprising a circularly arranged series of upwardly projecting expansible fingers,

each. finger having an inwardly facing pressure surface adjacent to its upper end, said expansible fingers extending being expanded outwardly into matching conical formations by the spreading action of the tapered wedging surface on said core being forced downwardly against the ring of pressure surfaces on said expansible fingers in a swaging operation so as to rigidly join said driving point to the lower portion of said pile shell before starting to drive the pile shell into the ground, said tapered wedging surface having an upper maximum diameter which is substantially larger than the internal diameter of said ring of pressure surfaces at the start of the swaging operation, said upper maximum diameter having a vertical spacing above said downwardly facing driving surface on said core which is substantially equal to or less than the vertical spacing of said ring of pressure surfaces above said upwardly facing driven surface within said point, whereby said tapered wedging surface will completethe outward swaging of said expansion fingers before said driving surface engages said driven surface to start the downward driving of the pile shell, the conical formation assumed by said expansible fingers constituting a tension transmitting driving taper and the conical formation assumed by said shell wall constituting a tension transmitting driven taper, through the engagement of which driving and driven tapers the downward driving blows on the driving core are transmitted to the pile shell for drawing the pile shell down into the ground under downwardly acting tension.

3. In pile apparatus of the class described, the combination of a cylindrical thin wall pile shell of substantially uniform diameter for the major portion of its length, a substantially cylindrical driving core freelyreciprocable throughout the length of said pile shell, said driving core having a cylindrical outside diameter almost equal to the cylindrical inside diameter of said pile shell, a driving head mounted on the lower end of said driving core having a downwardly and inwardly tapered wedging surface and having a downwardly facing driving surface below said wedging surface, a driving point at the lower .end of said pile shell of thicker metal than said pile shell and formed with an upwardly facing driven surface adapted to receive driving blows from the downwardly facing driving surface of said core in the pile driving operation, said driving point also including an end head of larger diameter than said pile shell and establishing a lower end closure closing off the bottom end of said pile shell, a cylindrical skirt extending upwardly from said end head within the lower end of said pile shell, a series of annularly spaced expansible fingers extending upwardly from said cylindrical skirt within said pile shell, each of said fingers having an inwardly extending pressure bead at its upper end, a reenforcing band surrounding said pile shell and said cylindrical skirt below the upper ends of said expansible fingers, said lower end of said pile shell and said expansible fingers being expanded out- I wardly into matching conical formations by the spreading action of the tapered wedging surface on said driving head being forced downwardly against the ring of pressure beads in a swaging operation so as to rigidly join said driving point to the lower end of said pile shell before starting to drive the shell into the ground, said tapered wedging surface having an upper maximum diameter which is substantially larger than the internal diameter of said ring of pressure beads, said upper maximum diameter having a vertical spacing above said downwardly facing driving surface on said core which is substantially equal to or slightly less than the vertical spacing of said ring of pressure beads above said upwardly facing driven surface within said point, whereby said tapered wedging surface will complete the outward swaging of said expansion fingers before said driving surface engages said driven surface to start the downward driving of the pile shell, the conical formation assumed by said expansible fingers constituting a tension transmitting driving taper and the conical formation assumed by said shell wall constituting a tension transmitting driven taper, throughthe engagement of which driving and driven tapers the downward driving blows on the driving core are transmitted from the driving head to the pile shell for drawing the pile shell down into the ground under downwardly acting tension applied to the lower portion of the pile shell.

4. In pile apparatus of the class described, the combination of a cylindrical thin wall pile shell of substantially uniform diameter for the major portion of its length, a substantially cylindrical driving core freely reciprocable throughout the length of said pile shell, said driving core having an outside diameter almost equal to the inside diameter of said pile shell, a driving head mounted on the lower end of said driving core having a downwardly and inwardly tapered wedging surface and having a downwardly facing driving surface below said wedging surface, a driving point at the lower end of said pile shell of thicker metal than said pile shell and formed with an upwardly facing driven surface adapted to receive driving blows from the downwardly facing driving surface of said core in the pile driving operation, said driving point also including an end head of larger diameter than said pile shell establishing a lower end closure closing off the bottom end of said pile shell, a cylindrical skirt extending upwardly from said end head within the lower end of said pile shell, a reinforcing band surrounding the lower portion of said pile shell and said cylindrical skirt a series of annularly spaced expansible fingers extending upwardly from said cylindrical skirt within said pile shell to a level substantially above the upper edge of said reinforcing band, each of said fingers being thicker at least at its upper end than the thickness of said pile shell, said lower end of the pile shell and said expansible fingers being expanded outwardly into matching conical formations by the spreading action of the tapered wedging surface on said driving head being forced downwardly against said expansible fingers in a swaging operation so as to rigidly join said driving point to the lower end of said pile shell before starting to drive the shell into the ground, said tapered wedging surface having an upper maximum diameter which is substantially larger than the internal diameter of said ring of expansible fingers, said upper maximum diameter having a vertical spacing above said downwardly facing driving surface on said core which is substantially equal to or slightly less than the vertical spacing of the upper ends of said expansible fingers above said upwardly facing driven surface within said point, whereby said tapered wedging surface will complete the outward swaging of said expansion fingers before said driving surface engages said driven surface to start the downward driving of the pile shell, the conical formation assumed by said expansible fingers constituting a tension transmitting driving taper and the conical formation assumed by said shell wall constituting a tension transmitting driven taper, through the engagement of which driving and driven tapers the downward driving blows on the driving core are transmitted from the driving head to the pile shell for drawing the pile shell down into the ground under tension.

5. The method of driving into the ground a relatively long, thin wall cylindrical pile shell which is of rigid fixed length from end to end, said pile shell having cylindrical openings at opposite ends thereof both of the same diameter, whereby one or more substantially similar thin wall cylindrical pile shells of rigid fixed length can be joined to the upper end of said first pile shell in the event that it should be desired to sink a deeper pile, which method comprises inserting into such pile shell a substantially cylindrical driving core that is freely reciprocable throughout the length of the pile shell, said driving core having a cylindrical outside diameter closely approximating the cylindrical inside diameter of said pile shell, but with "a circumferential free-slip clearance space therebetween which is continuously maintained throughout the entire pile driving operation and the subsequent core withdrawing operation, said driving core having its lower portion formed with a downwardly and inwardly tapered wedging surface which diminishes in radius toward the bottom end of said core, assembling the open bottom end of the pile down over a driving point composed of thicker metal than said pile shell, said driving point comprising a circularly arranged series of upwardly projecting expansible fingers each having an inwardly extending contact bead at its upper end, said series of expansible fingers fitting up into the inside of said pile shell, moving said driving core downwardly to cause its tapered wedging surface to engage said contact beads for expanding said expansion fingers outwardly into a conical formation, such outward expansion of said expansion fingers also expanding the surrounding side wall of said pile shell outwardly to deform it into a substantially corresponding conical formation, the conical formation assumed by said expansible fingers constituting a driving taper and the conical formation assumed by said shell wall constituting a driven taper, through the engagement of which driving and driven tapers the downward driving blows on the driving core are transmitted to the pile shell, imparting such driving blows to the driving core for drawing the pile shell down into the ground primarily under the tension transmitted through said driving and driven tapers while still maintaining said free-slip clearance space between said driving core and said pile shell, and then withdrawing said driving core from the driven pile shell.

6. The method of driving into the ground a relatively long thin wall steel pipe pile shell which is of rigid fixed length from end to end and of cylindrical straight-sided construction with all points of its length of the same diameter, said pile shell having cylindrical openings at opposite ends thereof both of the same diameter, whereby one or more substantially similar thin wall cylindrical pile shells of rigid fixed length can be joined to the upper end of said first pile shell in the event that it should be desired to sink a deeper pile, which method comprises inserting into such pile shell a substantially cylindrical driving core that is freely reciprocable throughout the length of the pile shell, said driving core having a cylin-' drical outside diameter closely approximating the cylindrical inside diameter of said pile shell, but with a circumferential free-slip clearance space therebetween which is continuously maintained throughout the entire pile driving operation and the subsequent core withdrawing operation, said driving core having its lower portion formed with a downwardly and inwardly tapered wedging surface, assembling the open bottom end of said pile shell down over a driving point composed of thicker metal than said pile shell, said driving point comprising a series of expansible fingers fitting up into the inside of said pile shell, forcing said driving core downwardly to cause its tapered wedging surface to spread said expansion fingers outwardly into a conical formation, causing such outward expansion of said fingers to also deform the surrounding side wall of said pile shell outwardly into a substantially corresponding conical formation, the conical formation assumed by said expansible fingers constituting a tension transmitting driving taper and the conical formation assumed by said shell wall constituting a tension transmitting driven taper, imparting downward driving blows to the driving core which are transmitted through said driving and driven tapers to the lower portion of the pile shell, wherebythe pile shell is drawn down into the ground solely under the force of such driving blows acting in tension on the pile shell while still maintaining said free-slip clearance space between said driving core and said pile section throughout the entire pile driving operation, and then withdrawing said driving core from the driven pile shell, said driving point with its expansion fingers expanded outwardly into said deformed conical formation in the pile shell remaining in the ground in the base end of the driven pile shell after the driving core has been withdrawn.

7. In pile apparatus of the class described, the combination of cylindrical pile shell means comprising an upper cylindrical pile section of relatively large diameter and a lower cylindrical section of relatively small diameter, the lower end of said upper pile section overlapping the upper end of the lower pile section, a driving core comprising an upper core section having an outside diameter almost equal to the inside diameter of said upper pile section and fitting within said upper pile section, and a lower core section having an outside diameter almost equal to the inside diameter of said lower pile section and fitting within said lower pile section, a joint between said upper and lower pile sections comprising a relatively thick intervening band secured over the upper portion of said lower pile section for reinforcing the upper portion of said lower pile section, a circularly arranged series of expansible fingers carried by said intervening band and by said reinforced upper portion of said lower pile section and extending upwardly into the overlapping bottom end of the upper pile section, a downwardly and inwardly tapering wedging surface on said driving core adjacent to said joint, the lower end of said tapering wedging surface being of smaller diameter than the upper end of said intervening band, but the upper end of said tapering wedging surface being of larger diameter than the upper end of said intervening band, whereby said tapering wedging surface is operative under downward motion of said driving core to expand said expansible fingers, said expansible fingers and the surrounding lower portion of said upper pile section being expanded outwardly into matching conical formations by the spreading action of the tapered wedging surface on said core as it is forced downwardly against said expansible fingers, the conical formation assumed by said expansible fingers constituting a tension transmitting driving taper and the conical formation assumed by the wall of said upper pile section constituting a tension transmitting driven taper, through the engagement of which driving and driven tapers the downward driving blows on the driving core are transmitted to the upper pile section for drawing this upper pile section down into the ground under downwardly acting tension.

References Cited in the file of this patent UNITED STATES PATENTS 228,161 Adlam June 1, 1880 690,284 Hicks Dec. 31, 1901 777,351 Raymond Dec. 13, 1904 1,192,247 Upson et al. July 25, 1916 1,890,290 Hargreaves Dec. 6, 1932 1,893,011 Watt Jan. 3, 1933 2,334,386 Cortella Nov. 16, 1943 2,437,043 Riemenschneider et al. Mar. 2, 1948 2,467,826 Henderson Apr. 19, 1949 2,631,435 Emshwiller Mar. 17, 1953 2,684,577 Smith July 27, 1954 2,693,087 Quillinan Nov. 2, 1954 FOREIGN PATENTS 428,202 Germany Sept. 20, 1926 431,385 Great Britain 1935 

